The present invention relates to construction using Insulating Concrete forming Systems (ICFS), and more particularly to a new reinforced composite system for constructing insulated concrete structures.
Insulating Concrete Forming Systems (ICFS), which are currently known, act as forms for the construction of concrete walls, the end benefit is a wall which is already insulated and ready for the application of exterior and interior finish materials. The known ICFS currently in use comprise a pair of foam plastic panels connected by a plurality of ties or connectors. The panels are molded from expanded polystyrene (EPS) beads providing low density foam plastic panels which are used as a form to contain the concrete during placement. The EPS beads are expanded with high pressure steam, in molds that are confined by a large press.
An example of Known art U.S. Pat. No. 5,896,714 issued to Cymbala et al. on Apr. 27, 1999 comprises pairs of panels molded from EPS and connected by ties. The ties have opposed vertical flanges with web portions extending between. In one embodiment the flanges of the ties are molded within the panels, the web members extending between panels. In another embodiment the panels are formed with “T”-shaped slots amenable to accept the flanges of the ties.
Another example of known art is U.S. Pat. No. 6,170,220 issued to Moore, Jr. on Jan. 9, 2001 comprising opposing panels molded from EPS and using molded-in web members. The web members have attachment points that extend past the inside face of the panels, the connecters extend between and engage the attachment points of opposing panels.
Known art systems are limited in many respects due to the materials used, the manufacturing process and the configuration of the ties, webs and connectors. The EPS foam doesn't adhere to the ties and webs when using molded-in configurations causing a weak point in the panels at each tie or web location. In the slide-in configurations the molded slots penetrate deeply into the panels also creating a weakness at each penetration. There are no ties or webs located at the panel ends allowing the vertical joints to bulge or blowout during concrete placement. The panels are manufactured in small units approximately 12 inches to 16 inches in height and 36 inches to 48 inches in length, the size being limited by the strength of the low density EPS and the prohibitive cost of larger molds and more expensive machinery to contain the molds during the high pressure steam expansion process. EPS has a relatively low R-value per inch and the poor structural characteristic make it prone to damage during material handling and construction.
The tie configuration disclosed in Cymbala is typical of many of the known art systems, the webs of the ties comprising closely spaced members leaving little open space through the webs, in effect perforating the concrete at each tie location. In Moore, Jr. there are numerous connectors required between the panels to hold the pressure of the poured concrete. These restrictive configurations, and the close spacing of the ties, webs and connectors, create a structural weakness in the wall caused by the number of penetrations through the concrete, in addition they inhibit the natural flow of the concrete during placement increasing the difficulty of pouring the walls and causing honey comb in the concrete. The inherent weakness of the EPS makes it very difficult to vibrate the walls to increase the concrete flow and reduce the honey comb without causing the forms to bulge or blowout. In the molded-in tie and web configurations the inability of the EPS to bond to the flanges of the ties and web members allows the panels to split along the flanges under the pressure of the concrete during placement, causing the walls to bulge and blowout. In Moore, Jr. the large number of connectors that must be installed is time-consuming and the labor required is costly.
The use of EPS foam as a form material, the use of small unit sizes and the restrictive tie, web and connector configurations create difficulties that must be overcome. When using small unit sizes there are more units to set increasing the labor required to erect a wall. There are more horizontal and vertical joints increasing the possibility of blowouts during concrete placement and a greater amount of bracing is required to straighten and stabilize the walls. Great care must be taken while placing the concrete to prevent blowouts, the concrete must be placed slowly and in short lifts. Also when EPS foam is exposed to sunlight for any period of time it deteriorates causing a powder to form on the surface of the panels, thus when using finish materials which require a strong bond to the substrate special treatment is required to remove the deterioration. Because EPS does not readily accept most finish materials an additional substrate must be installed when using finish materials that bond directly to the wall, resulting in increased costs. A large amount of labor is required to prepare the numerous horizontal and vertical joints before the application of finish materials. Another downfall of the known art systems is the lack of an easy method for securing wall reinforcing, manual tying of the wall reinforcing is time-consuming and the extra labor required is costly.